1. Field of the Invention
The present invention relates to a cerdip type of solid-state image sensing device, a structure and a method for gripping the cerdip type of solid-state image sensing device for using in the interior of an image reading apparatus such as a copying machine, an image scanner, a facsimile or the like.
2. Description of the Prior Art
Generally, an image reading apparatus which is incorporated in an imaging apparatus and reads an image as an optical image by use of a solid-state image sensing device such as a CCD and so on is configured to read by focusing an object 53 on a solid-state image sensing device 61 through a focused lens 52 as shown in FIG. 10.
The used solid-state image sensing device 61 has a plurality of micro-photoelectric transfer devices (hereinafter, referred to as pixels each having normally a micro-size of several μm by several μm) in which a pixel line 31 is arranged in one straight line.
In such an image reading apparatus, a linear image focused by the focused lens 52 is positioned on the solid-state image sensing device 61 and the focused lens 52 or one linear pixel line 31 of the solid-state image sensing device 61 must be micro-motioned about X, Y and Z axes, in rotational directions of β and γ about Y and Z axes, respectively, (three axes and two rotational directions in five axes of X, Y, Z, β and γ axes) for adjusting a position thereof to read optical characteristic (focusing, magnification and so on) with a predetermined accuracy, as shown in FIG. 11.
Note that reference numeral 8 denotes an optical axis.
Here, a reason that adjustment is not effected with respect to an a axis about the X axis is as follows.
When the β and γ axes which are vertical with the pixel line is not adjusted, a distance between the focused lens 52 and solid-state image sensing device 61 is different every the pixel to deteriorate the accuracy of optical characteristic. On the contrary, since the X axis is parallel with the pixel line, the distance between the focused lens 52 and solid-state image sensing device 61 is not different every the pixel, and thus the optical characteristic is not subjected to an influence.
On the other hand, in recent, there may be used a solid-state image sensing device having three pixel lines 31a, 31b and 31c linearly arranged in every pixels R, G and B which have a peak of spectral sensitivity in Red, Green and Blue to read color images as shown in FIG. 12.
Normally, a high precision is required to position adjustment of the solid-state image sensing device in 5 axis directions. There is required a technic to accomplish such requirement in which if the solid-state image sensing device is attached to a frame, after position of the solid-state image sensing device is adjusted as described above, the position of the solid-state image sensing device is not deviated from the frame.
A reason why such technic is required is because of requiring readjustment even though the high precision for the adjustment is performed when the position of the solid-state image sensing device deviates from the frame on attachment and requiring disposal of an attached part in a case of adopting an attaching method which is not separatable, thereby bringing to a long positioning adjustment and resulting in a high cost attaching method.
The solid-state image sensing device 61 is, also, mounted on a base 12 within the imaging apparatus. The base 12 drives the solid-state image sensing device 61 and acts to transmit an electrical output signal of the solid-state image sensing device 61 according to an optical image to a control section (not shown) of the image reading apparatus after the electrical output signal is electrically processed.
If an object to be read in the image reading apparatus is an image, a line type of solid-state image sensing device in which a plurality of micro photoelectric transfer devices are disposed in one line is almost used. In this case, the image is read as a linear image. In a color image reading apparatus for reading a color image, a color solid-state image sensing device having three lines 31a, 31b and 31c in which pixels having a peak of spectral sensitivity in Red (hereinafter referred to as R), Green (hereinafter referred to as G) and Blue (hereinafter referred to as B) are arranged in three lines every R, G and B is used (see FIG. 12).
Furthermore, the solid-state image sensing device is classified in several kind by an outside structure (package structure). In recent, the cerdip type of solid-state image sensing devise is increasingly used even in an image reading apparatus for a low production cost.
FIG. 13 is a sectional view showing a basic structure of a conventional cerdip type of solid-state image sensing device (for color, herein).
The cerdip type of solid-state image sensing device has a construction as follows.
A CCD chip 63 which is a chip of the solid-state image sensing device is mounted on a base 62 of ceramic. Pixel lines 31a, 31b and 31c are formed on the CCD chip 63. A lead frame 65 is secured to the base 62 by means of sealed glass 64 and is electrically connected to the CCD chip 63 by wire-bonding between the lead frame 65 and CCD chip 63 with a lead wire 68. A wind frame 66 is bonded with the sealed glass 64. A transparent cover glass 67 is secured to the wind frame 66 to seal the CCD chip 63.
As described above, in the image reading apparatus, the linear image focused by the focused lens 52 is positioned on the solid-state image sensing device 61 and the solid-state image sensing device 61 must be micro-motioned along or about the five axes of X, Y, Z, β and γ as shown in FIG. 11 for adjusting a position thereof to read the optical characteristic (focusing, magnification and so on) with a predetermined accuracy during a producing step of the image reading apparatus.
Then, normally, an accuracy of the positioning adjustment of the solid-state image sensing device is μm or 0.001° order in all the five axes.
Here, the optical axis 8 in FIGS. 11 and 13 corresponds to a direction of the Z axis in a coordinate.
Directions of the X and Y axes correspond to main and sub scanning directions, respectively in the image reading apparatus.
Further, α is about the X axis, β is about the Y axis and γ is about the Z axis.
It is necessary to grip the solid-state image sensing device 61 with a producing apparatus (not shown) on production to perform the positioning adjustment as described above.
It, then, is considered that the solid-state image sensing device is not directly gripped, the base on which the solid-state image sensing device is mounted is gripped as an object of gripping.
However, the base 12 has a problem in a point of stiffness since the base comprises a thin plate and normally, does not make of a material having a high stiffness.
Upon gripping of a base having a low stiffness, the gripping causes the base to deform resiliently to occur change of position of the solid-state image sensing device 61. There is no problem on this fact if a product has a low adjusting accuracy, but, if the solid-state image sensing device is used for an image reading apparatus to which a high accuracy should be requested, this deformation of the base becomes a large problem.
Under the aforementioned circumstances, it is desirable that the solid-state image sensing device is directly gripped as an object of gripping on production.
In prior art, the cerdip type of solid-state image sensing device which is economically advantageous, as described above has no any part suitable to grip. Namely, since a side 62a of the base 62 and a side 66a of the wind frame 66 are closing as shown in FIG. 14, there is no plane of gripping by a chuck.
Note that in FIG. 14, only a positional relationship of the base 62 and wind frame 66 is magnifically shown and the sealed glass 64 and cover glass 64 and so on are omitted. A side 61a may not be a gripped plane of a chuck for projection of the side of the sealed glass 64 as shown in FIG. 13.
As described above, there is no a cerdip type of solid-state image sensing device in which ability of gripping is considered in the prior art.
In a such condition, a gripping portion of the device must be provided on the base 12.
This results in elimination of adjusting accuracy of the image reading apparatus or a high cost of the image reading apparatus by no using the cerdip type of solid-state image sensing device. As a result, it is not compatible with an image reading quality and economics.